2 INSTITUTE OF SOCIAL ANTHROPOLOGY—PUBLICATION NO. 7 
zone around Paricutin Volcano, are the remaining 
predominantly Tarascan settlements in the tierra 
templada, the upper part of the plateau escarp- 
ment (2 percent of Tarascan population in 1940). 
Formerly an important part of the Tarascan 
Empire, the hot lands of the Tepalcatepec and 
Balsas Basins (tierra caliente, Jusio) have lost 
completely the last vestige of spoken Tarascan. 
A small number of Tarascan-speaking folk live 
in some of the larger mestizo towns adjacent to 
the main Tarascan area: Uruapan, Patzcuaro, 
Coeneo, Zacapu, Zamora. With the possible 
exception of a few old households in Uruapan, the 
presence of aboriginal speech in the large mestizo 
settlements probably represents a recent influx 
from rural areas (a desire for urban life, migration 
from the voleano-devastated areas) rather than 
linguistic remnants. 
THE PHYSIOGRAPHIC AREAS 
The Sierra.—The Tarascan “Sierra” is not a 
mountain chain; it is rather a volcanic plateau, 
whose average elevation is some 1,500 feet higher 
than that of the surrounding areas and whose 
surface has been roughened by large composite 
volcanoes, scores of small cinder cones, and ex- 
tensive lava flows (malpais). Lying within Mex- 
ico’s transcontinental volcanic axis, the Sierra is 
the locale of the country’s newest active volcano, 
Paricutin.’ Within the central part of the area 
elevations range from 6,900 feet to over 12,660 
feet (Cerro de Tancitaro). The altitude of the 
plateau increases from west to east. Elevations 
of towns in the western half of the Sierra range 
from 5,180 feet (Atapan) to 7,800 feet (Pamaté- 
cuaro);in the eastern half, from 8,040 feet (Sevina) 
to 8,460 feet (Cumachuén), the highest pueblo in 
the Sierra west of Lake PAtzcuaro. Even higher 
settlements (e. g. the rancho of Cruz Gorda, 
8,987 feet) exist southeast of the lake, and the 
highest point in Michoacan, the Cerro de San 
Andrés (12,840 feet), lies in the Sierra de Ozu- 
matlin, 62 km. east of Morelia. 
Tertiary and Quaternary vulcanism has pro- 
duced the major land forms in the Sierra (map 2). 
In age the volcanic forms range from probably 
Eocene to the present time. The oldest are mas- 
sive composite volcanoes, the highest and most 
8 The chief scientific references on the Paricutin Voleano include Ordéiiez 
(1945), Robles Ramos (1943), Pérez Pefia (1946), Mexico City Universidad 
Nacional Instituto de Geologia (1945). 
prominent landmarks in the area: Cerro de 
Tancitaro (12,660 feet), Cerro de Patamban 
(12,300 feet), Cerro de Quinseo (10,800 feet), 
Cerro el Zirate (10,955 feet). The flanks of these 
mountains are composed mainly of andesite with 
some pinkish rhyolite near the summits; small 
veins of mineral-bearing quartz sometimes occur 
within the andesite. Conical shape and radial 
drainage characterize these voleanoes, but most 
craters have been destroyed by erosion. Fre- 
quently erosion of soft consolidated ash situated 
between andesite flows has formed caves, which 
have acquired importance in Tarascan folklore. 
Cinder cones and lava flows, Pleistocene to 
Recent in age, represent the younger forms in the 
Sierra. The entire area is dotted with cones, 250 
to 700 feet high, with no apparent alinement. 
Most are composed of semiconsolidated ash, 
cinder, and large blocks of explosion remnants. 
Two types of cones occur: (1) the symmetrical 
cone with a well-developed, flat-floored crater, 
and (2) the breached cone, with one side partially 
destroyed, initially by explosion or lava flow and 
subsequently by erosion. Some cones are ribbed 
by radial drainage; others carry scars of surface 
slips; owing to porous surface materials, a few 
show little effects of erosion, in spite of high 
(35°-45°) angle slopes. 
Basaltic lava flows, originating usually from 
Pleistocene or Recent fissures in the sides of old 
volcanoes or occasionally from large cinder cones, 
have descended slopes in narrow corridors and 
have fanned out in wide expanses on gentle 
eradients. Fantastically rough surfaces charac- 
terize the flows, which form the Sierra’s badlands— 
agriculturally unproductive and barriers to horse 
and wheeled traffic. Comparative age of the 
flows can be roughly determined by the degree 
of rock decomposition and character of vegetation 
cover. In some flows, such as that south of 
Pomacuaran, depressions and crevasses are par- 
tially filled with alluvium; large areas are covered 
with a thin soil mantle; sizable pines and oaks 
cover most of the flow. These features evidence 
a long period of exposure. In contrast, the 
rough, blackened, almost treeless malpais north- 
west of Zacapu at the Sierra’s northern edge, 
appears to be a much younger flow. 
Volcanic activity in the Sierra has possibly been 
continuous from Eocene to the present day. 
Jorullo (1759) and Parfcutin (1943) represent 
